The present invention is directed to micro-hinges used in micro-electromechanical systems (MEMS) and micro-systems technology, and more particularly to an improved micro-hinge configuration and design adding robustness and strength to the hinging element.
The use of micro-hinges has become prevalent with the increased utilization and complexity of surface micro-machine components and systems. Typically used in the implementation of out-of-plane or vertically oriented micro-device designs, the micro-hinge is usually fabricated in a minimum two-layer, though typically three-layer, polysilicon process. Such a hinge 10, known as a staple hinge, is illustrated in FIG. 1, integrally connected with micro-mirror 12, and is used to attain out-of-plane motion. The multi-step fabrication process, includes depositing a first layer which is then patterned and etched. Next a second layer is deposited, patterned and etched in such a way that after removing any filling material, the first layer is free to move in a prescribed path, while being held in place by the second layer. This structure creates a rotating joint implemented in MEMS or micro-systems to permit for the mechanical movement required for micro-mirrors and other out-of-plane devices.
Drawbacks to existing micro-hinge designs include process complexity and cost of fabrication.
The inventors have also observed that the device layer of silicon-on-insulator (SIO) wafers are being used to form micro-structures such as mirrors, lenses and other out-of-plane or vertically oriented devices for integrated MEMS and micro-systems. The formation of such devices requires the use of micro-hinges to provide rotational freedom and mechanical support for these out-of-plane devices.
It is therefore considered useful to develop less complex and costly micro-hinges capable of providing the necessary mechanical integrity and strength to allow out-of-plane rotation or vertical movement of SOI device layer structures.
Provided is a micro-assembly including a micro-device formed on a device layer of a single crystal silicon substrate. A ribbon structure is formed on the device layer, where the ribbon structure is thinned to a thickness which is less than the thickness of the micro-device. A connection interface provides a connection point between a first end of the micro-device and a first end of a ribbon structure, wherein the ribbon structure and micro-device are integrated as a single piece.